Drive mechanism for a timer



Feb. 13, 1968 E. w. VOLAND ,4

DRIVE MECHANISM FOR A TIMER Filed Dec. 16, 1965 2 Sheets-Sheet 1 /N VENTOR- ELMO W. VOLAND AT TO RNEY Feb. 13, 1968 E. w. VOLAND 3,368,415

DRIVE MECHANISM FOR A TIMER Filed Dec. 16, 1965 2 Sheets-Sheet 2 INVENTOR. ELMO W. VOLAND ATTOR United States Patent 3,368,415 DRIVE MECHANISM FOR A TIMER Elmo W. Voland, Indianapolis, Ind., assignor to -P. R. Mallory & Co. Inc., Indianapolis, Ind., a corporation of Delaware Filed Dec. 16, 1965, Ser. No. 514,196 Claims. (Cl. 74142) ABSTRACT OF THE DISCLOSURE A drive mechanism for a shaft having a one-piece drive member which is pivotally and slidably mounted on the shaft for driving the shaft. One means for operating the drive member so as to rotate the shaft at one speed and another means for operating the drive member so as to rotate the shaft at another speed.

The present invention relates to timers and more particularly to the means and method for providing a new and novel drive mechanism for a timer.

There is presented herein a drive mechanism for a timer of the type having a plurality of cams for operating electric-a1 switches. The drive mechanism of the present invention is particularly attractive because it can be easily adapted to impart a periodic snap-action rotational motion to the camshaft of the timer as well as to rapidly advance the camshaft to a particular cycle starting point. Also, the drive mechanism has less moving par-ts and is easier to assemble than contemporary escapement mechanisms which are used to drive the camshafts of timers.

The drive mechanism of the present invention is characterized by a one piece drive member having a tang engaged with a ratchet wheel mounted on a camshaft and by the fact that said drive member is pivot-ally and slidably mounted about said camshaft. As the drive member is pivoted about the camshaft, it will slide to permit the engagement of the next tooth of the ratchet wheel. A spring means is provided for storing energy as the drive member is pivoted. The stored energy is the means for providing a snap-action rotational motion to the camshaft.

Other features of the present invention will become apparent as this specification progresses.

It is an object of the present invention to provide a novel drive mechanism for a timer which is simple, and easy to manufacture.

It is another object of the present invention to provide a drive mechanism for a timer which will impart a snapaction rotational motion to the camshaft of said timer.

It is another object of the present invention to provide a drive mechanism for a timer having a one piece drive member which is pivot-ally and slidably mounted about' the camshaft of said timer.

It is another object of the present invention to provide a drive mechanism for a timer which has a one piece drive member for rotating a camshaft of said timer and a first means for operating said drive member so as to rotate said ratchet wheel and asecond means for operating said drive member so as to rotate said ratchet wheel.

It is another object of the present invention to provide a drive mechanism for a timer which has a one piece drive member for rotating a ratchet wheel mounted to the camshaft of said timer and a solenoid means for operating said drive member so as to rotate said ratchet wheel.

The present invention, in another of its aspects, relates to novel features of the instrumentalities described herein for teaching the principal object of the invention and to the novel principles employed in the instrumentalities whether or not these features and principles may be used in the said object and/ or in the said field.

Other objects of the invention and the naturethereof will become apparent from the following description considered in conjunction with the accompanying drawings and wherein like reference numbers describe elements of similar function therein and wherein the scope of the invention is determined rather from the dependent claims.

For illustrative purposes, the invention will be described in conjunction with the accompanying drawings in which:

FIGURE 1 is an exploded perspective of the drive mechanism of the present invention.

FIGURE 2 is a view of the drive mechanism of the present invention illustrating the time-driven advance feature.

FIGURE 3 is a view of the drive mechanism of the present invention illustrating the rapid advance feature.

FIGURE 4 is a view of the drive mechanism of the present invention showing the use of a solenoid drive means for the rapid advance feature, said solenoid drive means being deenergized in said view.

FIGURE 5 is another view of the drive mechanism of the present invention showing the use of a solenoid drive means for the rapid advance feature, said solenoid drive means being energized in said View.

FIGURE 6 is a partial sectional view of the drive member and of the first means for pivoting and sliding the drive member.

Generally speaking the present invention is a drive mechanism for a shaft comprising: a ratchet wheel for rotating said shaft, said ratchet wheel being mounted on said shaft; a drive member having a tang engaged with said ratchet wheel for imparting rotation thereto, said drive member being pivot-ally and slidably mounted about said shaft; a means for periodically pivoting and sliding said drive member about said shaft so as to advance said ratchet wheel, said pivoting and sliding means being coupled to said drive member; a spring for storing energy as said drive member is pivoted, said energy'being a means for imparting a snap-action rotational motion to said shaft when said drive member is released by said pivoting and sliding means, said spring being connected to said drive member; and a means for preventing backward rotation of said ratchet wheel.

Referring now to the drawing, and particularly to the exploded perspective of FIGURE 1, the component parts of the present invention can be visualized in conjunction with the following description. The base plate 10' of metallic construction is the main support member for the drive mechanism of the present invention. The timer motor 11, which is a driving means having a constant speed rotational output, is mounted to the base plate 10"by means of the threaded standoffs 12 and the nuts 13. The timer motor 11 output shaft has a pinion gear 14 for engaging and driving the gear 15 which rotates the cam 16 which is on the hub 17 with said gear 15. There is a spring means 18 or biasing means connected between a tang 19 formed on the base plate 10 andatang 21 formed on the drive member 20. There is a cam follower 22 on the drive member 20 which is operated by the cam 16 and a drive tang 23 on said drive member 20 for'engaging teeth on the ratchet wheel .25. A back-up pawl 24 is secured to the base plate 10 so as to engage the teeth on the ratchet wheel 25.

The ratchet wheel '25 is mounted on the camshaft 26 so as to rotate said camshaft when said ratchet wheel is driven. There are a plurality of control earns 27 mounted on the camshaft 26 so as to be rotated thereby.

A second cam follower 28 is mounted on the drive member 20 at an end opposite to the cam follower 22. The second cam follower 28 is operated by the cam 29 which is rotated on a common shaft with the gear 33. A pinion gear 32 which is adapted to be rotated with the gear 31 is engaged with the gear 33. The gear 31 is driven by a pinion gear 30 which is secured to the rotor of the motor 34. The motor 34 is secured to the base plate by means of the threaded studs 35 and the nuts 36.

The drive member 20 has a slotted or elongated hole 37 which pivots about and slides on the camshaft 26 on the reduced diameter portion 38. The purpose of this slotted hole will become more apparent as the specification progresses.

Referring now to FIGURE 2, a view showing the operation of the timed-advance feature of the drive mechanism can be seen. The pinion gear 14 drives the gear 15 in the direction of the arrow shown on the gear 15. The cam 16, which rotates in the direction of the arrow shown on said cam, moves the cam follower 22, and, consequently, the drive member so as to store energy in the spring means 18. It will be noted that the drive tang 23 on the drive member 20 is still in engagement with a tooth on the ratchet wheel 25 and that the slotted hole 37 is such that the drive member 20 can move in the direction of the arrow shown on said drive member 20. It will also be noted that the cam 29 is in a position so as not to be in contact with the cam follower 28.

Referring now to FIGURE 3, a view of the drive mechanism showing the operation of the rapid advance feature can be seen. The cam 29 is moving the cam follower 28 so as to pivot the drive member 20 about the small portion 38 of the camshaft 26, thereby storing energy in the spring means 18. It will be noted that the cam follower 22 is not in contact with the cam 16 and that the drive member 20 has moved in the direction away from the cam 29 as far as is permitted by the small portion 38 of the camshaft 26 in the elongated slot 37. The sliding action of the drive member 20 is caused by the drive tang 23 moving up the tooth of the ratchet wheel 25 as said drive member is pivoted about the camshaft 26.

Referring now to FIGURE 4, an optional driving mechanism can be seen. A solenoid means 39 has been added in lieu of the motor 34, gears 30, 31, 32 and 33, cam 29, and the cam follower 28. The plunger 43 of the solenoid means 39 is connected to the optional drive member 40 at the point 46. The optional drive member 40 is pivoted about the narrow portion 38 of the camshaft 26 and has an elongated slot 44 to permit a sliding action. The drive member 40 has a drive tang 45 which is engaged with the teeth of the ratchet wheel 25. There is a saw-tooth cam 41 adapted to be rotated by the timer motor 11 at the same speed as the pinion gear 14. (The timer motor 11 is not shown in FIGURE 4.) Thus sawtooth cam 41 periodically closes the contacts of the switch assembly 42 which are connected to the solenoid means 39.

It can be seen that the plunger 43 of the solenoid means 39 is extended and the solenoid means is deenergized. Hence, the spring means 18 is not storing energy.

Referring now to FIGURE 5, a view of the optional drive mechanism with the solenoid means 39 energized can be seen. The saw-tooth cam 41 has advanced in the direction of the arrow shown thereon so as to close the contacts of the switch assembly 42, thereby energizing the solenoid means 39. It can be seen that the plunger 43 of the solenoid means 39 has pulled in, that the spring means 18 has been extended to store energy, and that the switch assembly 42 contacts are about to be opened as the saw-tooth cam 41 advances further.

With the above description of components in mind, and by making reference to the drawing figures, the following analysis of operation will serve to convey the functional details of the drive mechanism of the present invention.

As stated previously, the present invention is a drive mechanism for a timer of the type having a plurality of cams mounted on a rotating shaft and a plurality of electrical switches operated by said cams. A time-driven advance is required for advancing the timer through the programmed timing cycle. This time-driven advance must be a snap-action advance in order toopen and close the contacts of the switches without excessive contact damage. An escapement mechanism usually provides the necessary snap-action advance. A rapid advance is required to advance the timer to a particular cycle starting point or through a particular cycle. The rapid advance obviously has to rotate the camshaft much faster than the timedriven advance. The means and methods for obtaining both the time-driven advance and the rapid advance will be discussed in the following paragraphs of this specification.

Referring again to FIGURE 2, it can be seen that as the cam 16 rotates in the direction of the arrow shown on said cam, the drive member 20 will be pivoted about the small portion 38 of the camshaft 26 so as to store energy in the spring means 18. As the cam 16 rotates further, the drive member 20 will slide in a direction towards said cam and the drive tang 23 will move back to engage an adjacent tooth on the ratchet wheel 25. As the cam 16 rotates still further, the cam follower 22 will roll down the incline of said cam so as to release the energy stored in the spring means 18, thereby advancing the ratchet wheel 25 one tooth space. The ratchet wheel 25 will, therefore, be advanced one tooth space each time the cam 16 is rotated through one complete revolution. Since the timer motor 11 rotates at a constant speed the movement of the ratchet wheel in the manner just described will constitute a time-driven advance.

Referring again to FIGURE 3, it can be seen that the cam 29 has operated the cam follower 28 to cause the drive member 20 to pivot about small portion 38 of the camshaft 26 to store energy in the spring means 18. The pivoting and sliding of the drive member 20 will cause the drive tang 23 to move to an adjacent tooth on the ratchet wheel 25. As the cam 29 rotates further to permit the cam follower 28 to roll down the incline of said cam, the energy stored in the spring means 18 wil be released to cause the drive member to advance the ratchet wheel 25 one tooth space. The drive motor 34 rotates at a fairly high speed as compared with the timer motor 11 and will, therefore, advance the ratchet wheel 25 much faster. This faster advance constitutes a rapid advance feature for the timer.

An optional rapid advance feature is shown in FIG- URES 4 and 5. In the optional embodiment, a solenoid means 39 is used to pivot and slide the drive member 40 so as to advance the ratchet wheel 25. The means for periodically energizing the solenoid means is the sawtooth cam 41 which is driven by the timer motor 11 and the switch assembly 42. Referring now to FIGURE 4, it can be seen that the saw-tooth cam 41 will close the switch assembly 42 contacts one time for each tooth on said saw-tooth cam for each revolution of the pinion gear 14 which is on' the shaft of the timer motor 11. Hence, the solenoid means 39 will be energized at a fast rate to rapidly advance the ratchet wheel 25.

The saw-tooth cam 41 and the switch assembly 42 is an electrical pulsing means for periodically energizing the solenoid means 39. Other types of electrical pulsing means could be used to accomplish the same function. For instance, an electronic timing circuit having a silicon controlled rectifier output could be used to energize the solenoid.

Although the drawing and discussion to this point have concerned the utilization of two driving means, it is within the purview of this disclosure to have a single driving means using the basic drive member which is pivotally and slidably mounted about the shaft means. For example, many timers do not have or require a rapid advance feature but do require a timed-advance feature.

The drive mechanism of the present invention, as hereinbefore described in one of its embodiments, is merely illustrative and not exhaustive in scope. Since many widely different embodiments of the invention may be made without departing from the scope thereof, it is intended that all matter contained in the above description and shown in the accompanying drawing shall be interposed as illustrative and not in a limiting sense.

What is claimed is:

1. A drive mechanism for a shaft comprising: a ratchet wheel for rotating said shaft, said ratchet wheel being mounted on said shaft; a drive member having means normally engaged with said ratchet wheel for imparting rotation thereto, said drive member being pivotally and slidably mounted on said shaft; means for periodically pivoting and sliding said drive member about said shaft so as to advance said ratchet wheel, said pivoting and sliding means being coupled to said drive member; bias means for storing energy as said drive member is pivoted, said energy imparting a snap action rotational motion to said shaft when said drive member is released by said pivoting and sliding means, said bias means being connected to said drive member; and means cooperatively associated with said ratchet wheel substantially preventing backward rotation of said ratchet wheel.

2. A drive mechanism as in claim 1 wherein said means for periodically pivoting and sliding said drive member is a cam means, said cam means being coupled to and driven by a driving means having a constant speed rotational output.

3. A drive mechanism as in claim 1 wherein said means for periodically pivoting and sliding said drive member about said shaft is a solenoid, said solenoid being energized by a cam-switching means operated by a driving means having a constant speed rotational output.

4. A drive mechanism as in claim 1 wherein said means for periodically pivoting and sliding said drive member about said shaft means is a solenoid, said solenoid being periodically energized by an electrical pulsing means.

5. A drive mechanism for a shaft comprising: a ratchet wheel for rotating said shaft, said ratchet wheel being mounted on said shaft; a drive member having means normally engaged with said ratchet wheel for imparting rotation thereto, said drive member being pivotally and slidably mounted on said shaft; bias means for storing energy as said drive member is pivoted about said shaft, said energy imparting a snap action rotational motion to said shaft when said energy is released, said bias means being connected to said drive member; first means for pivoting and sliding said drive member about said shaft so as to advance said ratchet wheel, said first pivoting and sliding means being coupled to a first end of said drive member; second means for pivoting and sliding said drive member about said shaft so as to advance said ratchet wheel, said second pivoting and sliding means being coupled toa second end of said drive member; and means cooperatively associated with said ratchet wheel substantially preventing backward rotation of said ratchet wheel.

6. A drive mechanism as in claim 5 wherein said first means for pivoting'and sliding said drive member about said shaft is a cam means, said cam means being coupled to and driven by a driving means having a constant speed rotational output.

7. A drive mechanism as in claim 5 wherein said second means for pivoting and sliding said drive member about said shaft is a cam means, said cam means being coupled to and driven by a motor.

8. A drive mechanism as in claim 5 wherein said second means for pivoting and sliding said drive member about said shaft is a solenoid, said solenoid being periodically energized by an electrical pulsing means.

9. A drive mechanism for a timer of the type having a plurality of cams mounted on a camshaft comprising: a

ratchet wheel for rotating said camshaft, said ratchet wheel being mounted on said camshaft; a drive member having a tang engaged with said ratchet wheel for imparting rotation thereto, said drive member being pivotally and slidably mounted on said camshaft; a spring for storing energy as said drive member is pivoted about said camshaft, said energy being a means for imparting a snap action rotational motion to said camshaft when said energy is released, said spring being connected to said drive member; a cam means for periodically pivoting and sliding said drive member about said camshaft so as to advance said ratchet wheel, said cam means being coupled to and driven by a driving means having a constant speed rotational output; a solenoid for pivoting and sliding said drive member about said camshaft so as to advance said ratchet wheel, said solenoid being connected to said drive member; a cam-switching means driven by said driving means for intermittently energizing said solenoid; and means cooperatively associated with said ratchet wheel substantially preventing backward rotation of said ratchet wheel.

10. A drive mechanism as claimed in claim 1, wherein said means of said drive member normally engaged with said ratchet wheel is a tang.

11. A drive mechanism as claimed in claim 1, wherein said bias means is a spring means.

12. A drive mechanism as claimed in claim 5, wherein said means of said drive member normally engaged with said ratchet wheel is a tang.

13. A drive mechanism as claimed in claim 5, wherein said bias means is a spring bias means.

14. A drive mechanism for a shaft comprising: a ratchet wheel carried by said shaft for rotating said shaft; a drive member having means normally engaged with said ratchet wheel for imparting rotation thereto, said drive member including a slot cooperatively associated with a portion of said shaft so that said drive member is pivotally and slidably mounted on said shaft, said slot having a length substantially longer than the diameter of said portion of said shaft cooperatively associated with said drive member; cam follower means carried by said drive member; cam means having peripheral rise and fall contours on which said cam follower means ride for pivoting and sliding said drive member about said shaft; spring bias means connected to and having its major axis at an angle with respect to the perpendicular of the major axis of said drive member, said bias means storing energy as said drive member is pivoted about said shaft, release of said stored energy imparting a snap action rotational motion to said shaft.

15. A drive mechanism as claimed in claim 14, wherein said cam follower means includes spaced apart first and second cam followers and wherein said cam means includes first and second cam means on which said first and second cam followers ride, said first and second cams acting independently to pivotally and slidably displace said drive member.

References Cited UNITED STATES PATENTS 2,868,026 1/1959 Finehout et al 74-142 X 2,895,340 7/1959 Nicolaus 74142 3,115,785 12/1963 Simmons 74142 X 3,151,490 10/1964 Kessler 74-142 FRED C. MATTERN, JR., Primary Examiner.

C. I. HUSAR, Examiner. 

